Changing and Measuring Consistency

Abstract

A measuring device comprising at least one mixer structure to receive a fibre suspension sample from at least one process part. Each mixer structure is provided with a measuring unit, a feeding valve for feeding feed liquid into a sample line for pushing the sample in the sample line towards the measuring unit, a mixing valve structure for feeding dilution liquid into the mixer structure The mixer structure mixes the flowing sample and the dilution liquid with one another in order to reduce the consistency of the sample. The measuring device measures from the first part of the mixed sample one property of the fibre suspension and the measuring device measures from the second part of the mixed sample a further property.

Description

FIELD[0001]The invention relates to a method and an arrangement for changing consistency and to a method and a measuring device for measuring the properties of a sample. The invention also relates to a computer program according to the method.BACKGROUND[0002]For instance in paper, board and pulp industry a need has arisen to carry out measurements of stock for supervising and controlling the process. Stock refers to suspension that includes liquid, particles of a solid such as fibres and possibly sticks and some gas. The idea of the measurements is to determine the properties of wood fibres to be used for making paper or board, such as length, thickness or the fibre wall thickness or other stock properties, such as freeness.[0003]Generally the sample taken from the process is to be diluted in order to analyze it. A sample that is too consistent may cause a measuring device or an analyzer to clog up. A sample that is too consistent may also cause for instance a measurement error, if ...

AI Technical Summary

Benefits of technology

[0005]It is an object of the invention to provide improved methods and a measuring device, an arrangement and a computer program implementing the methods. Thus, the invention relates to a method for changing the consistency of a sample for a process including fibre suspension. The method also comprises receiving a fibre suspension sample from at least one process part to at least one sample line, each sample line comprising feeding feed liquid into the sample line for pushing the sample forward in the sample line, feeding dilution liquid to a mixer structure and mixing the flowing sample and the dilution liquid with one another in order to reduce the consistency of the sample in the mixer structure.

[0009]The invention further relates to a computer program for carrying out a computer process, which while running changes the consistency of a sample taken from a process including fibre suspension. The computer process comprises receiving a fibre suspension sample from at least one process part to at least one sample line, and each sample line comprises feeding feed liquid into the sample line for pushing the sample forward in the sample line, feeding dilution liquid into a mixer structure and mixing the flowing sample and the dilution liquid with one another in order to reduce the consistency of the sample in the mixer structure.

[0011]The method and the arrangement of the invention provide several advantages. The structure of the arrangement is simple and small in size and therefore advantageous to produce. The consistency is accurately and rapidly controlled. The need for dilution liquid is insignificant.

Problems solved by technology

A sample that is too consistent may cause a measuring device or an analyzer to clog up.

A sample that is too consistent may also cause for instance a measurement error, if an excessive amount of individual objects, such as fibres or sticks, simultaneously fall on the observation area of the measuring device.

The result of a minimum amount requirement of a representative sample and the dilution need of the sample is often that the sample processing system to be dimensioned in accordance with the amount of diluted sample becomes large and expensive.

The use of excessive dilution liquid also increases the costs and also the environmental load.

This may significantly prolong the total time required for analyzing the sample.

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